Phase I study of IMGN901, a CD56-targeting antibody-drug conjugate, in patients with CD56-positive solid tumors

Background IMGN901 is a CD56-targeting antibody-drug conjugate designed for tumor-selective delivery of the cytotoxic maytansinoid DM1. This phase 1 study investigated the safety, tolerability, pharmacokinetics, and preliminary activity of IMGN901 in patients with CD56-expressing solid tumors. Methods Patients were enrolled in cohorts of escalating IMGN901 doses, administered intravenously, on 3 consecutive days every 21 days. A dose-expansion phase accrued patients with small cell lung cancer (SCLC), Merkel cell carcinoma (MCC), or ovarian cancer. Results Fifty-two patients were treated at doses escalating from 4 to 94 mg/m(2)/day. The maximum tolerated dose (MTD) was determined to be 75 mg/m(2). Dose-limiting toxicities included fatigue, neuropathy, headache or meningitis-like symptoms, chest pain, dyspnea, and myalgias. In the dose-expansion phase (n = 45), seven patients received 75 mg/m(2) and 38 received 60 mg/m(2) for up to 21 cycles. The recommended phase 2 dose (RP2D) was established at 60 mg/m(2) during dose expansion. Overall, treatment-emergent adverse events (TEAEs) were experienced by 96.9 % of all patients, the majority of which were Grade 1 or 2. The most commonly reported Grade 3 or 4 TEAEs were hyponatremia and dyspnea (each 8.2 %). Responses included 1 complete response (CR), 1 clinical CR, and 1 unconfirmed partial response (PR) in MCC; and 1 unconfirmed PR in SCLC. Stable disease was seen for 25 % of all evaluable patients who received doses ≥60 mg/m(2). Conclusions The RP2D for IMGN901 of 60 mg/m(2) administered for 3 consecutive days every 3 weeks was associated with an acceptable tolerability profile. Objective responses were observed in patients with advanced CD56+ cancers.

Efficacy and toxicity of treatment with the anti-CTLA-4 antibody ipilimumab in patients with metastatic melanoma after prior anti-PD-1 therapy

Background:

Recent phase III clinical trials have established the superiority of the anti-PD-1 antibodies pembrolizumab and nivolumab over the anti-CTLA-4 antibody ipilimumab in the first-line treatment of patients with advanced melanoma. Ipilimumab will be considered for second-line treatment after the failure of anti-PD-1 therapy.

Methods:

We retrospectively identified a cohort of 40 patients with metastatic melanoma who received single-agent anti-PD-1 therapy with pembrolizumab or nivolumab and were treated on progression with ipilimumab at a dose of 3 mg kg⁻¹ for a maximum of four doses.

Results:

Ten percent of patients achieved an objective response to ipilimumab, and an additional 8% experienced prolonged (>6 months) stable disease. Thirty-five percent of patients developed grade 3–5 immune-related toxicity associated with ipilimumab therapy. The most common high-grade immune-related toxicity was diarrhoea. Three patients (7%) developed grade 3–5 pneumonitis leading to death in one patient.

Conclusions:

Ipilimumab therapy can induce responses in patients who fail the anti-PD-1 therapy with response rates comparable to previous reports. There appears to be an increased frequency of high-grade immune-related adverse events including pneumonitis that warrants close surveillance.

Application of Sequencing, Liquid Biopsies, and Patient-Derived Xenografts for Personalized Medicine in Melanoma

Targeted therapies and immunotherapies have transformed melanoma care, extending median survival from ∼9 to over 25 months, but nevertheless most patients still die of their disease. The aim of precision medicine is to tailor care for individual patients and improve outcomes. To this end, we developed protocols to facilitate individualized treatment decisions for patients with advanced melanoma, analyzing 364 samples from 214 patients. Whole exome sequencing (WES) and targeted sequencing of circulating tumor DNA (ctDNA) allowed us to monitor responses to therapy and to identify and then follow mechanisms of resistance. WES of tumors revealed potential hypothesis-driven therapeutic strategies for BRAF wild-type and inhibitor-resistant BRAF-mutant tumors, which were then validated in patient-derived xenografts (PDX). We also developed circulating tumor cell-derived xenografts (CDX) as an alternative to PDXs when tumors were inaccessible or difficult to biopsy. Thus, we describe a powerful technology platform for precision medicine in patients with melanoma.

SIGNIFICANCE

Although recent developments have revolutionized melanoma care, most patients still die of their disease. To improve melanoma outcomes further, we developed a powerful precision medicine platform to monitor patient responses and to identify and validate hypothesis-driven therapies for patients who do not respond, or who develop resistance to current treatments.

Protocol for the CONVERT trial-Concurrent ONce-daily VErsus twice-daily RadioTherapy: an international 2-arm randomised controlled trial of concurrent chemoradiotherapy comparing twice-daily and once-daily radiotherapy schedules in patients with limited stage small cell lung cancer (LS-SCLC) and good performance status

INTRODUCTION

Concurrent ONce-daily VErsus twice-daily RadioTherapy (CONVERT) is the only multicentre, international, randomised, phase III trial open in Europe and Canada looking at optimisation of chemoradiotherapy (RT) in limited stage small cell lung cancer (LS-SCLC). Following on from the Turrisi trial of once-daily versus twice-daily (BD) concurrent chemoradiotherapy, there is a real need for a new phase III trial using modern conformal RT techniques and investigating higher once-daily radiation dose. This trial has the potential to define a new standard chemo-RT regimen for patients with LS-SCLC and good performance status.

METHODS AND ANALYSIS

447 patients with histologically or cytologically proven diagnosis of SCLC were recruited from 74 centres in eight countries between 2008 and 2013. Patients were randomised to receive either concurrent twice-daily RT(45 Gy in 30 twice-daily fractions over 3 weeks) or concurrent once-daily RT(66 Gy in 33 once-daily fractions over 6.5 weeks) both starting on day 22 of cycle 1. Patients are followed up until death. The primary end point of the study is overall survival and secondary end points include local progression-free survival, metastasis-free survival, acute and late toxicity based on the Common Terminology Criteria for Adverse Events V.3.0, chemotherapy and RTdose intensity.

ETHICS AND DISSEMINATION

The trial received ethical approval from NRES Committee North West-Greater Manchester Central (07/H1008/229). There is a trial steering committee, including independent members and an independent data monitoring committee. Results will be published in a peer-reviewed journal and presented at international conferences.

TRIAL REGISTRATION NUMBER

ISRCTN91927162; Pre-results.

Survival of patients with advanced metastatic melanoma: The impact of novel therapies

The survival of advanced metastatic melanoma has been greatly improved within the past few years. New therapeutic strategies like kinase inhibitors for BRAF-mutant melanoma and immune checkpoint blockers proved to prolong survival times within clinical trials, and many of them have already entered routine clinical use. However, these different treatment modalities have not yet been tested against each other, which complicate therapy decisions. We performed an explorative analysis of survival data from recent clinical trials. Thirty-five Kaplan-Meier survival curves from 17 trials were digitised, re-grouped by matching inclusion criteria and treatment line, and averaged by therapy strategy. Notably, the survival curves grouped by therapy strategy revealed a very high concordance, even if different agents were used. The greatest survival improvement was observed with the combination of BRAF plus MEK inhibitors as well as with Programmed-death-1 (PD1) blockers with or without cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) blockers, respectively, with these two treatment strategies showing similar survival outcomes. For first-line therapy, averaged survival proportions of patients alive at 12 months were 74.5% with BRAF plus MEK inhibitor treatment versus 71.9% with PD-1 blockade. This explorative comparison shows the kinase inhibitors as similarly effective as immune checkpoint blockers with regard to survival. However, to confirm these first trends for implementation into an individualised treatment of melanoma patients, data from prospective clinical trials comparing the different treatment strategies head-to-head have to be awaited.

Future perspectives in melanoma research: meeting report from the "Melanoma Bridge": Napoli, December 3rd-6th 2014

The fourth "Melanoma Bridge Meeting" took place in Naples, December 3-6th, 2014. The four topics discussed at this meeting were: Molecular and Immunological Advances, Combination Therapies, News in Immunotherapy, and Tumor Microenvironment and Biomarkers. Until recently systemic therapy for metastatic melanoma patients was ineffective, but recent advances in tumor biology and immunology have led to the development of new targeted and immunotherapeutic agents that prolong progression-free survival (PFS) and overall survival (OS). New therapies, such as mitogen-activated protein kinase (MAPK) pathway inhibitors as well as other signaling pathway inhibitors, are being tested in patients with metastatic melanoma either as monotherapy or in combination, and all have yielded promising results. These include inhibitors of receptor tyrosine kinases (BRAF, MEK, and VEGFR), the phosphatidylinositol 3 kinase (PI3K) pathway [PI3K, AKT, mammalian target of rapamycin (mTOR)], activators of apoptotic pathway, and the cell cycle inhibitors (CDK4/6). Various locoregional interventions including radiotherapy and surgery are still valid approaches in treatment of advanced melanoma that can be integrated with novel therapies. Intrinsic, adaptive and acquired resistance occur with targeted therapy such as BRAF inhibitors, where most responses are short-lived. Given that the reactivation of the MAPK pathway through several distinct mechanisms is responsible for the majority of acquired resistance, it is logical to combine BRAF inhibitors with inhibitors of targets downstream in the MAPK pathway. For example, combination of BRAF/MEK inhibitors (e.g., dabrafenib/trametinib) have been demonstrated to improve survival compared to monotherapy. Application of novel technologies such sequencing have proven useful as a tool for identification of MAPK pathway-alternative resistance mechanism and designing other combinatorial therapies such as those between BRAF and AKT inhibitors. Improved survival rates have also been observed with immune-targeted therapy for patients with metastatic melanoma. Immune-modulating antibodies came to the forefront with anti-CTLA-4, programmed cell death-1 (PD-1) and PD-1 ligand 1 (PD-L1) pathway blocking antibodies that result in durable responses in a subset of melanoma patients. Agents targeting other immune inhibitory (e.g., Tim-3) or immune stimulating (e.g., CD137) receptors and other approaches such as adoptive cell transfer demonstrate clinical benefit in patients with melanoma as well. These agents are being studied in combination with targeted therapies in attempt to produce longer-term responses than those more typically seen with targeted therapy. Other combinations with cytotoxic chemotherapy and inhibitors of angiogenesis are changing the evolving landscape of therapeutic options and are being evaluated to prevent or delay resistance and to further improve survival rates for this patient population. This meeting's specific focus was on advances in combination of targeted therapy and immunotherapy. Both combination targeted therapy approaches and different immunotherapies were discussed. Similarly to the previous meetings, the importance of biomarkers for clinical application as markers for diagnosis, prognosis and prediction of treatment response was an integral part of the meeting. The overall emphasis on biomarkers supports novel concepts toward integrating biomarkers into contemporary clinical management of patients with melanoma across the entire spectrum of disease stage. Translation of the knowledge gained from the biology of tumor microenvironment across different tumors represents a bridge to impact on prognosis and response to therapy in melanoma.

Ipilimumab in the real world: the UK expanded access programme experience in previously treated advanced melanoma patients

Before licensing, ipilimumab was first made available to previously treated advanced melanoma patients through an expanded access programme (EAP) across Europe. We interrogated data from UK EAP patients to inform future clinical practice. Clinicians registered in the UK EAP provided anonymized patient data using a prespecified variable fields datasheet. Data collected were baseline patient characteristics, treatment delivered, toxicity, response, progression-free survival and overall survival (OS). Data were received for 193 previously treated metastatic melanoma patients, whose primary sites were cutaneous (82%), uveal (8%), mucosal (2%), acral (3%) or unknown (5%). At baseline, 88% of patients had a performance status (PS) of 0-1 and 20% had brain metastases. Of the patients, 53% received all four planned cycles of ipilimumab; the most common reason for stopping early was disease progression, including death from melanoma. Toxicity was recorded for 171 patients, 30% of whom experienced an adverse event of grade 3 or higher, the most common being diarrhoea (13%) and fatigue (9%). At a median follow-up of 23 months, the median progression-free survival and OS were 2.8 and 6.1 months, respectively; the 1-year and 2-year OS rates were 31 and 14.8%, respectively. The 2-year OS was significantly lower for patients with poorer PS (P<0.0001), low albumin concentrations (P<0.0001), the presence of brain metastases (P=0.007) and lactate dehydrogenase levels more than two times the upper limit of normal (P<0.0001) at baseline. These baseline characteristics are negative predictors of benefit from ipilimumab and should be taken into consideration before prescription.

Dabrafenib and its use in the treatment of metastatic melanoma

Approximately 50% of melanomas have mutations in the gene encoding BRAF. In recent years, new targeted therapies have transformed the landscape of metastatic melanoma treatment. Dabrafenib, a potent kinase inhibitor of mutated BRAF, has been showed to have high response rates with a rapid onset of response, as well as improved overall and progression-free survival when compared with chemotherapy. Dabrafenib in combination with trametinib, a MEK inhibitor, has demonstrated higher responses and improved clinical efficacy compared with monotherapy. Toxicity is distinct compared with chemotherapy but manageable. This article summarizes the pharmacology, key clinical trial data as well as practical experience with dabrafenib in clinical practice, and future directions.

Abstract 2432: A technology platform for personalized medicine in melanoma

We developed patient derived xenografts (PDX), performed whole exome sequencing (WES) and analyzed circulating tumor DNA (ctDNA) to complement clinical management of four melanoma patients. Synchronous treatment of patients and mice showed that PDX responses mirrored those of the patients’ tumor to BRAF inhibitors. PDXs were used to test second-line treatments in relapsed patients and to validate WES-based therapies in tumors that did not have a BRAF mutation. Longitudinal analysis of ctDNA was predictive of responses to targeted and immunotherapies, and to determine mechanisms of resistance. Thus, we describe a powerful combination of techniques for personalized medicine in melanoma and discuss the challenges and limitations of implementing these novel technologies in patient management.

Citation Format: Maria R. Girotti, Dominic Rothwell, Amaya Viros, Amit Kumar Mandal, Kok Haw J. Lim, Gabriela Gremel, Simon Furney, Malin Pedersen, Jane Rogan, Jacqueline Swan, Alberto Fusi, Ged Brady, Paul Lorigan, Caroline Dive, Richard Marais. A technology platform for personalized medicine in melanoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2432. doi:10.1158/1538-7445.AM2015-2432

Abstract 1094: Deciphering driver mechanisms for tumorigenesis in BRAF/NRAS double wild-type melanoma through integration of heterogeneous genome-wide datasets

In cutaneous melanoma, the most lethal form of skin cancer, BRAF is mutated in ∼45% of cases and NRAS in a further ∼20% of cases. The lack of known drivers in the remaining proportion of samples represents a challenge for personalized medicine. We hypothesize that the BRAF/NRAS double wild-type (WT) samples are a heterogeneous group driven by multiple events that arise independently. We performed whole exome sequencing (WES) and complimentary RNA-seq of 23 tumor tissue samples from 21 patients. Six of these tumors were WT for BRAF and NRAS, so we studied these cases further. The SNV load in the WT samples is more variable than the BRAF or NRAS driven melanomas. The median number of SNVs/Mb (± SD) for BRAF mutant (n = 9), NRAS mutant (n = 7) and BRAF WT/ NRAS WT (n = 6) samples were: 12.2 ± 8.0, 42.2 ± 82.7 and 12.6 ± 90.2 respectively. Next we analyzed the TCGA cutaneous melanoma cohort where there are 154 BRAF and 92 NRAS mutated and 76 BRAF WT/NRAS WT samples. The median numbers of SNVs (± SD) were 374 ± 638.3, 577 ± 518.3 and 146.5 ± 1221.6 respectively. The p-value for the comparisons BRAF vs. WT and NRAS vs. WT were 0.087 and 0.002 respectively (two-tailed Mann-Whitney test). We identified the somatic mutations that are specifically enriched for double wild-type samples and observed that the top two hits, NF1 (30.2% in double WT vs. 5.7% otherwise) and KIT (15.8% in double WT vs. 0.8% otherwise) are known driver gene candidates for wild-type melanomas, but we also find other novel candidate driver genes. Thus, we present a framework for identification of driver mutations and therapeutic targets in double wild-type melanomas and integration of these types of data with other large datasets such as those derived from RNA-seq and RPPA will assist in the development of approaches to stratify double wild-type patients for targeted or immune-therapies.

Citation Format: Amit Mandal, Maria Romina Girotti, Amaya Viros, Gabriela Gremel, Elena Galvani, Rebecca Lee, Kok Haw Jonathan Lim, Simon J. Furney, Paul Lorigan, Richard Marais. Deciphering driver mechanisms for tumorigenesis in BRAF/NRAS double wild-type melanoma through integration of heterogeneous genome-wide datasets. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1094. doi:10.1158/1538-7445.AM2015-1094

Abstract 5024: Implications of MAPK pathway inhibition on monocytes and tumor-associated macrophages in melanoma

Plasticity in T-cell populations during response and onset of resistance to targeted therapy has been well documented. More recently, macrophage-derived tumor necrosis factor has been described to drive resistance to MAPK pathway inhibition, yet little is known on the adaptation of tumor-associated macrophage populations to treatment and disease progression in human melanoma.

To test for alterations in macrophage abundance following resistance to MAPK pathway inhibition, we applied a fluorescence-based co-staining strategy on melanoma specimens, representing tissue collected from patients before treatment and at relapse. In addition, we established in vitro co-culture systems to study the paracrine effects of melanoma cells on various aspects of monocyte differentiation and macrophage activation in the background of MAPK inhibition and resistance.

Resistance to targeted therapy was found to be associated with an increase in the number of tumor-resident macrophages. In vitro co-culture of melanoma cell lines with monocytes isolated from the peripheral blood of healthy donors or with CSF1-differentiated macrophages in the presence or absence of MAPK inhibition led to profound changes in monocyte/macrophage marker expression, indicating a direct interplay between the two cell populations upon MAPK pathway inhibition. Our data show that macrophages play an integral role in the changing immune-microenvironment during the course of MAPK pathway inhibition. Elucidation of mechanisms driving these processes will result in strategies to optimize treatment combinations and consecutive treatment outcomes for melanoma patients.

Note: This abstract was not presented at the meeting.

Citation Format: Gabriela Gremel, Maria Romina Girotti, Amaya Viros, Garry Ashton, Helen Bradley, Elena Galvani, Rebecca Lee, Alberto Fusi, Paul Lorigan, Richard Marais. Implications of MAPK pathway inhibition on monocytes and tumor-associated macrophages in melanoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5024. doi:10.1158/1538-7445.AM2015-5024

Abstract 2683: Simultaneous inactivation of TP53 and loss of PTEN diminish response to targeted therapy in V600EBRAF mutant melanoma

Numerous cancers are driven by mutationally activated kinases, many of which can be employed to define subsets of cancers and therefore patients most likely to benefit from treatment with rationally designed targeted therapies. Defining the landscape of genetic alterations that participate in cancer transformation provides insight into the diversity of clinical responses observed to targeted treatments. Here, we identified concurrent mutational inactivation of the tumor suppressors TP53 and PTEN as a mechanism of resistance to BRAF inhibitors in melanomas harboring mutant V600EBRAF.

Defects in TP53 function and PTEN loss occur in 17% and 12% of malignant melanomas respectively, rendering cells dependent on CHK1 to maintain normal cell cycle progression. We demonstrate that CHK1 inhibition increases sensitivity to a variety of alkylating agents and targeted therapies in V600EBRAF mutant, TP53/PTEN deficient cell lines and patient derived xenografts. Inhibition of CHK1 concurrently with the induction of either DNA damage or replication stress leads to ‘‘mitotic catastrophe’’ and cell death in our in vitro and in vivo models of TP53/PTEN deficient tumors. In the case of externally applied cellular stress from chemotherapeutics, our results suggest CHK1 inhibition may sensitise this genetically defined subset of melanomas to such treatments.

Our results provide some insight into the heterogeneity of clinical outcomes observed when treating BRAF mutant melanomas with BRAF inhibitor and suggest a need for comprehensive screening of TP53 and PTEN inactivation in these patients.

Citation Format: Elena Galvani, Kelly Brooks, Franziska Baenke, Maria Romina Girotti, Gabriela Gremel, Amit Kumar Mandal, Amaya Viros, Clare McManus, Matthew Smith, Kok Haw Jonathan Lim, Rebecca Lee, Alberto Fusi, Paul Lorigan, Richard Marais. Simultaneous inactivation of TP53 and loss of PTEN diminish response to targeted therapy in V600EBRAF mutant melanoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2683. doi:10.1158/1538-7445.AM2015-2683

Epigenetic activation of a cryptic TBC1D16 transcript enhances melanoma progression by targeting EGFR

Metastasis is responsible for most cancer-related deaths, and, among common tumor types, melanoma is one with great potential to metastasize. Here we study the contribution of epigenetic changes to the dissemination process by analyzing the changes that occur at the DNA methylation level between primary cancer cells and metastases. We found a hypomethylation event that reactivates a cryptic transcript of the Rab GTPase activating protein TBC1D16 (TBC1D16-47 kDa; referred to hereafter as TBC1D16-47KD) to be a characteristic feature of the metastatic cascade. This short isoform of TBC1D16 exacerbates melanoma growth and metastasis both in vitro and in vivo. By combining immunoprecipitation and mass spectrometry, we identified RAB5C as a new TBC1D16 target and showed that it regulates EGFR in melanoma cells. We also found that epigenetic reactivation of TBC1D16-47KD is associated with poor clinical outcome in melanoma, while conferring greater sensitivity to BRAF and MEK inhibitors.

Pembrolizumab versus Ipilimumab in Advanced Melanoma

BACKGROUND

The immune checkpoint inhibitor ipilimumab is the standard-of-care treatment for patients with advanced melanoma. Pembrolizumab inhibits the programmed cell death 1 (PD-1) immune checkpoint and has antitumor activity in patients with advanced melanoma.

METHODS

In this randomized, controlled, phase 3 study, we assigned 834 patients with advanced melanoma in a 1:1:1 ratio to receive pembrolizumab (at a dose of 10 mg per kilogram of body weight) every 2 weeks or every 3 weeks or four doses of ipilimumab (at 3 mg per kilogram) every 3 weeks. Primary end points were progression-free and overall survival.

RESULTS

The estimated 6-month progression-free-survival rates were 47.3% for pembrolizumab every 2 weeks, 46.4% for pembrolizumab every 3 weeks, and 26.5% for ipilimumab (hazard ratio for disease progression, 0.58; P<0.001 for both pembrolizumab regimens versus ipilimumab; 95% confidence intervals [CIs], 0.46 to 0.72 and 0.47 to 0.72, respectively). Estimated 12-month survival rates were 74.1%, 68.4%, and 58.2%, respectively (hazard ratio for death for pembrolizumab every 2 weeks, 0.63; 95% CI, 0.47 to 0.83; P=0.0005; hazard ratio for pembrolizumab every 3 weeks, 0.69; 95% CI, 0.52 to 0.90; P=0.0036). The response rate was improved with pembrolizumab administered every 2 weeks (33.7%) and every 3 weeks (32.9%), as compared with ipilimumab (11.9%) (P<0.001 for both comparisons). Responses were ongoing in 89.4%, 96.7%, and 87.9% of patients, respectively, after a median follow-up of 7.9 months. Efficacy was similar in the two pembrolizumab groups. Rates of treatment-related adverse events of grade 3 to 5 severity were lower in the pembrolizumab groups (13.3% and 10.1%) than in the ipilimumab group (19.9%).

CONCLUSIONS

The anti-PD-1 antibody pembrolizumab prolonged progression-free survival and overall survival and had less high-grade toxicity than did ipilimumab in patients with advanced melanoma. (Funded by Merck Sharp & Dohme; KEYNOTE-006 ClinicalTrials.gov number, NCT01866319.).